Thrust vectoring exhaust nozzles which achieve a varying thrust vector in a single plane are well known in the art. One such nozzle, a two dimensional convergent-divergent arrangement wherein a substantially rectangular flow passage is defined laterally by two parallel, spaced apart sidewalls, and vertically by two movable flap assemblies. Each flap assembly further includes a convergent flap, pivotable into the exhaust gas stream for varying the area of the nozzle throat, and a divergent flap hinged at its leading edge to the trailing edge of the corresponding convergent flap and independently movable for defining both the vertical discharge vector and expansion rate of the exhaust gas stream.
Such two dimensional nozzles provide effective, single plane thrust vectoring, typically in the vertical or pitch direction, without overly complicated linkage or other components. As with any aircraft application, weight is a critical factor, thus simple and effective designs are favored over more complicated and hence heavier arrangements.
The advantages of a multiplane, i.e., both yaw and pitch, thrust vectoring nozzle are also well known and highly desirable. Prior art designs of such multiplane thrust vectoring nozzles, however, have not matched the simplicity and light weight of the single plane, 2-D convergent-divergent nozzle discussed above. The highly desirable capability of the prior art multiplane thrust vectoring nozzles must therefore be traded off against the increased weight and complexity such designs entail. It may therefore be the choice of the airframe designer to settle for the advantage of a single plane thrust vectoring arrangement and to forego the undesirable weight penalty thus far inherent in the multiplane thrust vectoring nozzles.
There is thus a need for a multiplane thrust vectoring exhaust nozzle which is able to achieve such function without adding overly complex and weighty components.